This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A195660 #13 Aug 28 2024 13:16:30 %S A195660 4096,433500,11682296,153802520,1301236304,8155899320,41180193352, %T A195660 176740657340,668845118276,2290966142762,7241521734020,21437333168798, %U A195660 60123048359816,161217291701134,416373921218580,1041997475699102,2539265644237492,6050425313244116 %N A195660 Number of ways to place 11n nonattacking kings on a vertical cylinder 22 X 2n. %C A195660 Vertical cylinder: a chessboard where it is supposed that the columns 1 and 22 are in contact (number of columns = 22, number of rows = 2n). %H A195660 V. Kotesovec, <a href="https://oeis.org/wiki/User:Vaclav_Kotesovec">Non-attacking chess pieces</a> %H A195660 <a href="/index/Rec#order_12">Index entries for linear recurrences with constant coefficients</a>, signature (14, -89, 340, -870, 1572, -2058, 1968, -1365, 670, -221, 44, -4). %F A195660 Recurrence: a(n) = -4*a(n-12) + 44*a(n-11) - 221*a(n-10) + 670*a(n-9) - 1365*a(n-8) + 1968*a(n-7) - 2058*a(n-6) + 1572*a(n-5) - 870*a(n-4) + 340*a(n-3) - 89*a(n-2) + 14*a(n-1). %F A195660 G.f.: (1 + 4082*x + 376245*x^2 + 5977500*x^3 + 27440106*x^4 + 43897316*x^5 + 25742850*x^6 + 5340248*x^7 + 353057*x^8 + 5622*x^9 + 23*x^10)/((x-1)^10*(2*x-1)^2). %F A195660 a(n) = (4480441703*n - 59644067185)*2^n + 10913705/36288*n^9 + 219791627/20160*n^8 + 6663742261/30240*n^7 + 1542837967/480*n^6 + 314791170001/8640*n^5 + 311982683023/960*n^4 + 6333872421866/2835*n^3 + 56561301500209/5040*n^2 + 46445710897861/1260*n + 59644067186. %Y A195660 Cf. A195655, A195650, A137432. %K A195660 nonn %O A195660 1,1 %A A195660 _Vaclav Kotesovec_, Sep 22 2011